14.1 Properties Of Alcohols Flashcards
Functional group of alcohols
-OH
Hydroxyl group
Use of methanol
Hugh performance fuel - efficient combustion
Important chemical feedstock
Use of ethanol
Used in alcoholic drinks
Fuel
Solvent
Feedstock
Naming alcohols
Find the longest carbon chain
Number the Carbon(s) on which there are hydroxyl groups
Ending of -ol or -diol depending on number of hydroxyl groups
What is volatility?
Tendency of a substance to vaporise
Which have higher BPs - alkanes or alcohols?
Alcohols
Which are more volatile - alkanes or alcohols?
Alkanes
Which dissolves better in water - alkanes and alcohols?
Alcohols
Bonds in alkanes
Non polar bonds, as the electronegativity values of Carbon and Hydrogen are quite similar
Intermolecular forces are weak London forces - lower BP
Bonds in alcohols
Alcohols have a polar O-H bond due to difference in negativity between Oxygen and Hydrogen
Alcohol molecules are polar
Intermolecular forces will be London forces and hydrogen bonds between polar O-H groups
Why do alcohols have a higher boiling point?
There are hydrogen bonds holding the alcohol molecules together
These require more energy to overcome than the weaker London forces, so there is a higher boiling point
Why are alcohols more soluble in water?
Water is a polar molecule, so alcohols can dissolve in water, as hydrogen bonds can form between the polar O-H group of the alcohol and the water
What happens to solubility as hydrocarbon chain length increases?
The influence of O-H group becomes smaller, so solubility decreases
What is a primary alcohol?
When the Carbon with the O-H group is attached to 2 Hydrogens and 1 Alkyl group
What type of alcohol is methanol?
Primary alcohol
